A data processing method by a data sending apparatus is described. The method includes receiving a data packet from a PDCP layer, where the data packet is used as an RLC SDU. The method further includes encapsulating the RLC SDU into at least one RLC PDU, where each one of the at least one RLC PDU includes a header and a payload. The payload carries data from a single RLC SDU. It can be learned that a transmit end no longer performs concatenation processing at the RLC layer on the data packet. In this way, concatenation processing at the transmit end is reduced, and processing complexity and processing latency are further reduced. In addition, processing at a receive end also becomes simpler and more efficient.